1. Field of the Invention
The present invention relates to photographic apparatus and, more particularly, to an improved mechanism for preventing double exposure in such apparatus having a self cocking shutter and a piezoelectric generator for flash operation.
2. Description of the Prior Art
In cameras of the type having self cocking shutter, i.e., shutters which are automatically cocked by the return of the body release member, it is known in the art to provide means for disabling the shutter to prevent a second shutter actuation prior to film advance. Generally such double exposure prevention means have taken the form of linkages that block the body release member of the camera and do not allow a second exposure to be made until after a subsequent film advance operation has been completed. The linkage is connected to the film metering mechanism and the blockage of the body release member is removed during the film advance operation.
Recently, apparatus has been developed in which a plurality of flashlamps, each fireable by means of an electric pulse generated by a piezoelectric crystal, are assembled in a multilamp array. In one such array, all of the lamps are aligned in the same direction and each lamp has its own reflector. A switching mechanism is provided, internal to the array, for properly sequencing firing of the individual lamps. In photograhic apparatus adapted to utilize such an array, a piezoelectric crystal striking mechanism is provided, including a firing spring with an associated hammer, movable from a latched position to strike the piezoelectric crystal and thereby generate an electric pulse. In addition, a cocking mechanism is provided for moving the firing spring to its latched position subsequent to each actuation. Whether this cocking function is performed automatically in conjunction with some other function of the camera, such as film advance, or manually by the camera operator, it is desirable to disable the shutter of the camera until the cocking function has been performed to guard against the possibility of an attempted flash exposure before the flash firing mechanism has been cocked. Likewise, it is desirable to disable both the shutter and the flash-firing mechanism subsequent to each activation until the film has been advanced.